1. Field of Invention
This invention relates to an endoscope which is used for performing a procedure inside a body cavity or passageway and is more particularly directed towards an endoscope in the form of a mini-rigid ureteroscope which is used to perform medical procedures classified as diagnostic endoscopic examinations and therapeutic endoscopic procedures. The mini-rigid ureteroscope has an elongated shaft including a first elongated sheath tube having a deflectable distal section and a second elongated semi-rigid sheath tube which encloses a major portion of the first elongated sheath tube. The deflectable distal section extends beyond the distal end of the second semi-rigid elongated sheath tube. The endoscope is adapted to be inserted into the ureter of a patient for performing a medical examination and/or procedure within the ureter. This invention also relates to a method for casting a housing of a predetermined shape around an endoscope frame to form a fluid tight seal around working channels, viewing means for a fiber optic image bundle channel having a fiber optic image bundle and fiber optic light carrying means, all forming a part of the endoscope. This invention also relates to an image means for an instrument having a rod-like image transferring means wherein the rod-like image transferring means is rigidly attached to the instrument at a selected location along its length and wherein a slidably supporting means slidably supports the rod-like image transferring means at least at one location along the length to permit relative movement between the rod-like image transferring means and the instrument.
2. Description of the Prior Art
Endoscopes with an elongated shaft for viewing a body canal and for performing a surgical procedure within the body canal are known in the art. Typical of these devices, is an endoscope with tapered shaft of U.S. Pat. No. 4,986,258 which replaced withdrawn U.S. Pat. No. 4,961,414 and rigid endoscope with flexible tip covered in U.S. Pat. No. 4,802,461. A mini-scope catheter adapted to perform diagnostic procedures in smaller body parts, such as, for example, the bile duct or interior of the gall bladder, and which is constructed to allow the operator to control the deflection of a catheter tip is disclosed in U.S. Pat. No. 4,899,732.
The endoscope with tapered shaft disclosed in U.S. Pat. No. 4,986,258 utilizes a plurality of stages which are either step tapered or uniformly tapered to provide a distal section, a central section and a proximal section. The various stages or sections may be formed by a plurality of coaxially aligned tubes of decreasing diameters or could be formed of a single elongated shaft which is machined to provide the desired tapered surface along its length with the distal end having the smaller geometrical dimension. The transition zones between the three stages of the endoscope occur at about each third of the length and the transition for a two stage endoscope is approximately at the one half length or mid-point location.
U.S. Pat. No. 4,986,258 discloses that the final stage may include a flexible tip portion at the distal end of the shaft which is controllable from an endoscope handle. A mechanism for deflecting the flexible tip of a rigid endoscope, which could be used for such a flexible tip in an endoscope with taper shaft, is disclosed in U.S. Pat. No. 4,802,461 noted above. The tip end of the tube is barely flexible, relative to the length of the tube. Wires connected to opposite ends of the flexible tip provide the user with the means to control the flexing of the distal tip.
Also, U.S. Pat. No. 4,899,732 discloses a catheter, which has a deflectable catheter tip and which includes at least one lumen, which can be used to receive a stylet or to pass a contrast medium. In addition, the mini-catheter includes two optical filament channels, one for carrying light to the distal end and the other for transmitting an optical image to the proximal end of the catheter.
The cross-sections of each the above described endoscopes and mini-scope are generally circular in shape and provide a distal tip which can be utilized to be inserted in to the orifice of the body canal or duct, as the case may be.
It is also known in the art to utilize a ureteroscope to perform certain procedures in the urethra, bladder, ureter or kidney. Generally, ureteroscopes are used to view the ureter or perform procedures in the ureter. As such, the endoscopes include a semi-rigid elongated shaft to enable the urologist or user to insert the distal tip through the urethra orifice and to advance the same through the bladder and through the intra-mural ureter to some location in the ureter.
Surgical procedures may be performed within the urinary system such as destroying and/or removing bladder stones, ureteral stones, kidney stones or examining calyces of the kidney. It is also known to use mechanical accessories or working tools such as lithotriptors, electrohydraulic probes, stone baskets or laser fiberguides to break up a stone and to perform other known procedures. The flexibility of the tip and the length of the semirigid section are important features of a ureteroscope in the urology field. The reason that the above features are important is that the anatomical path of the ureter between the bladder and the kidney is not a straight line and, in some cases, can be quite torturous.
Ureteroscope sheaths for performing procedures in the ureter are known in the art. Typical of such ureteroscope sheaths are devices offered for sale and sold by the CIRCON ACMI Division of Circon Corporation, which are identified as Catalog Numbers HUS-10S and HUS-10L. These Catalog Number devices are basically the same ureteroscope sheath with Catalog Number HUS-10L having a longer elongated shaft to enable the urologist to advance the ureteroscope sheath further into the ureter.
The Catalog Numbers HUS-10S and HUS-10L ureteroscopes are constructed to have a semi-rigid section which is operatively attached to a relatively rigid proximal section forming a two diameter stepped elongated shaft. The two sections are joined with the proximal end of the semi-rigid section mechanically attached to the distal end of the relatively rigid proximal section at a point approximately midway along the elongated shaft. A tapered joint or a step-tapered joint is provided depending on the manufacturing assembly of the ureteroscope sheath. The degree of taper at the transitional zone or joint area is controlled by metal polishing and other known manufacturing techniques.
Each of the above known endoscopes, flexible mini-catheters and the ureteroscope sheaths have at least one working channel. The endoscopes and mini-catheter include a fiber optic image bundle. A fiber optic light carrying means may be dispersed around the working channels and fiber optic image bundle channel or may be located in a separate dedicated fiber optic light bundle channel.
None of the known prior art devices disclose an endoscope having an elongated shaft wherein one transitional zone exists between a semi-rigid proximal section and deflectable distal section wherein the transitional zone is located generally in the distal area, such as the first quarter length, of the elongated shaft, as measured from the distal tip. Further, the endoscope of the present invention may have the flexible distal section thereof terminate in a distal portion which has a geometrically shaped cross-sectional area having at least one protuberance. In the preferred embodiment, the distal section is triangular shaped and has a plurality of working channels, which may be of the same or different sizes and shapes, a fiber optic image bundle channel having a fiber optic image bundle and a fiber optic light carrying means. The endoscope of the present invention may be used to view the interior of a cavity or passageway and the working channels may be utilized for performing procedures within the cavity or passageway.
As the state-of-the-art advances in the ureteroscopy field, it has developed that endoscopes having a shorter elongated shaft wherein the distal section of the shaft is flexible and the proximal section of the shaft is semi-rigid are preferred. Specifically, such endoscopes are preferred for performing visual examinations within the urinary system and for performing various procedures and providing treatment for diseases of the urinary tract. Typical of articles which disclose the use of a rigid endoscope in the management of ureteral diseases are: (1) URETEROSCOPE WITH RIGID INSTRUMENTS IN THE MANAGEMENT OF DISTAL URETERAL DISEASE by Tobias M. Goodman which appeared in the Journal of Urology, August, 1984, Volume 132, at pages 250 (The "Goodman Publication"); and (2) URETERAL LASER LITHOTRIPSY USING THE PULSOLITH by Demetrius H. Bagley, M.D., Michael Grasso, M.D., Mohammed Shalaby, M.D. and Magdy Abass El-Akkad, M.D. which appeared in the Journal of Endourology, Volume 3, Nov. 1, 1989, at Pages 91-98 (The "Bagley et al. Publication")
The Goodman Publication discloses that the rigid ureteroscope allows for ureteroscopic manipulation of the ureter because of the anatomical arrangement of the body. Ureteroscopy with a rigid instrument usually is performed with the patient under anesthesia. The Goodman Publication also describes the procedure is performed by introducing the distal tip of the rigid ureteroscope into the urethra and passing the instrument transurethrally. The ureteroscope is then introduced into the ureteral orifice. Usually, this is done visually through an eyepiece or by observing a video image developed by a video camera attached to the ureteroscope. The Goodman Publication specifically discloses the necessity of having the exterior of the sheath of the ureteroscope very smooth and of small caliber such that the ureter will adjust to the increasing size of the instrument as it is transversed throughout the ureter. The procedure described in the Goodman Publication demonstrates the applicability of ureteroscopy to every day problems encountered by a urologist.
The Bagley et al. Publication discloses use of a Pulsolith.TM. Laser as a highly effective tool for the destruction of ureteral calculi including those of calcium oxalate monohydrate. The small flexible fibers required to be used with the laser are delivered with rigid or flexible endoscopes throughout the upper urinary tract. The Bagley et al. Publication discloses that the endoscopic access to the distal ureteral calculi with rigid instruments is extremely successful. However, when calculi are located in mid or upper ureteral locations, flexible ureteroscopy is generally more successful in accessing those more proximal locations.